Civil Engineering Reference
In-Depth Information
6 Work Holding in the Vice
EQUIPMENT
Machine vice
The main vice you will be using will be the machine vice. This is normally a
substantial item made from iron castings. It is worth buying a good quality ma-
chine vice as it should last a lifetime.
The jaws of a machine vice should preferably be hardened and ground,
although soft jaws are very useful as well. The jaws must also be vertically
aligned with the milling machine's table and head. This can be checked with
a lever dial test indicator. If you have a knee machine you should check the
verticality of the vice by winding the table up and down and also by moving
the quill or head up and down. Both should show the same (zero) reading.
Normally you would put the vice onto the milling machine either square or
at 90 degrees to the travel of the X axis of the mill. If you get into the habit of
clocking the vice up square you are less likely to make a mistake. If square-
ness of the job does not matter, still clock the vice up, as the next job may
be important and if you put the vice on roughly square but not clocked, you
may forget the vice is not true and scrap the next workpiece. In industry, the
next person may come along and assume the vice is square and they may
scrap their work and they will not be very pleased. Yes, I know you should not
assume the vice is square but in a professional environment you expect pro-
fessional workmanship.
If you must put the vice on out of square for quickness, either leave a mes-
sage on the vice or remove the vice after use. It can remain on the milling ma-
chine, but remove the clamping bolts and turn the vice at an angle so people
can see it is out of square.
When clocking the vice with the lever dial test indicator, concentrate on get-
ting it correct at both ends of the vice jaw. It may be that the middle of the jaw
is slightly bowed. If the bow is a matter of a thou or two this will not matter, but
any larger bow should be investigated and corrected before moving on.
